Question

How do you solve `a²-a-1=0` by completing the square?

Answer 1

`a= 1/2+sqrt5/2 or a=1/2-sqrt5/2`

Explanation:

`a^2-a-1=0 or a^2-a-(1/2)^2-5/4=0 or (a-1/2)^2-5/4=0 or (a-1/2)^2=5/4`
`:.a-1/2=sqrt5/2or a-1/2= - sqrt5/2 :. a= 1/2+sqrt5/2 or a=1/2-sqrt5/2`
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